A fire tube steam boiler is a boiler where the combustion gases from the burner are channeled through tubes that are surrounded by the fluid to be heated. The boiler body is the pressure vessel and contains the fluid. In most cases, this fluid is water that will circulate for heating purposes or become steam for use in processing.
Each set of tubes through which the combustion gas passes, before making a turn, is considered a "step". Consequently, a three-step boiler will have three sets of pipes with the outlet located at the rear of the boiler.
Biomass steam boilers recover the heat generated during the biomass combustion process to heat the water in the boiler exchanger circuit. The hot water is then diverted to the heating circuit.
Occasionally it is necessary to remove the ashes generated by biomass combustion and clean the burner.
The pressure of the steam is directly related to its temperature. So process temperature will require steam used to be at a specified pressure. For example, a process requires that needs temperatures at 150°C will require steam delivered at 6 Kg/cm2 or higher.
